1. Field of the Invention
Aspects of the present invention relate to a communication method for a device in a network system and a system for managing network devices; more particularly, to a communication method for a device in a network system and a system for managing network devices which allow a management server on an external network to initiate communication with devices on an internal network by selecting and designating one of the devices to maintain a connection with the management server.
2. Related Art
A network printing system is a system in which multiple user terminals share at least one image forming device connected through an internal office or home network. A user requests an operation related to image forming, such as printing a document, to a desired image forming device among the pool of image forming devices.
Generally in a network printing system the management of multiple image forming devices is performed by a management server. The management server monitors the state of the image forming devices via a network, such as the Internet, and controls the image forming devices based on the state information transmitted from the image forming devices.
The image forming devices report their state information (e.g., current amount of toner, the number of printed pages) by transmitting to the management server at scheduled times. After an image forming device initiates a connection, via the network, to the management server, the management server receives the state information of the image forming device, transmits new schedule information or a desired command to the image forming device, and then terminates the connection.
In the network printing system described above, however, a management server located on an external network cannot initiate communication to an image forming device located on an internal network behind a firewall and must wait for the image forming device to connect with the management server at a scheduled time. The firewall protects the local network and the image forming devices from externally initiated connections. The firewall permits connections from inside the local network to outside the external network but restricts access initiated from the external network to the local network. For the management server located on the external network to issue a command to or update a schedule on a specific image forming device, the management server must wait for the required image forming device to initiate a connection to the management server, thus delaying a response to the command or update until the scheduled time.